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I’ve been getting some SNES Mini and 1-chip consoles to repair lately. The most common issues are:

Black screen on all games

Black screen on some games. Other games, such as Mario Kart, freeze at the publisher splash screen

The latter issue is exactly the same problem as what happens when you simply remove the sound module from an SHVC console. It’s seems to be caused when the CPU can’t communicate with the sound hardware for any reason. In some cases, it’s due to some broken traces on the board somewhere. But as I’ve mentioned before, it’s often due to a failed APU. On GPM-01/02 and RGB-01/02 revisions it can also be due to a failed S-SMP.

With a bad APU or sound module, the console freezes here on Mario Kart.

Or here on many Koei games, like my test game, Super Mahjong Taikai

The first problem, however, is something that I can’t normally fix. Unless there’s some obvious problem, such as rust or corrosion in the cartridge slot or some broken traces, then I just give up on those boards and set them aside.

Something I discovered quite by accident, however, is that a bad APU can actually cause the first problem as well as the second.

Recently I grabbed one of those black screen SNES mini boards to steal its APU for a 1-chip board I was repairing that had a known bad APU (it would freeze at the “KOEI” screen). Once I installed the APU from the black screen SNES mini into the 1-chip board, the 1-chip board also began displaying only a black screen, even on games that were previously loading to the publisher screen and then freezing. At first I thought I must have accidentally left a solder bridge connecting some legs of the chip or screwed up in some other way with bad soldering, but after checking and rechecking, that wasn’t the issue. I then removed the APU and the board started loading games and then freezing again at the publisher screen, just as it had been doing originally.

To test my theory that the APU itself was causing the black screen issue, I went over to the SNES mini board from which I had salvaged the APU. I powered it on without any APU installed at all and, sure enough, it would load games up to the publisher’s logo and then freeze.

To be certain, I took one more known good 1-chip board that was only missing an APU and installed the APU from the Mini board into it. It started showing just a black screen when I installed it. Once removed, it again loaded games and froze at the publisher logo.

Finally, I went over to my stack and found two 1-chip boards that I had labelled “black screen”. I removed the APUs from both of them. One of them started loading games and freezing at the publisher screen, showing that it had the same problem as the Mini board (i.e. just a bad APU). The other board, unfortunately, still just showed a black screen. It must have had some other issue.

But the major point here is that when troubleshooting boards that show only a black screen, it’s possible the APU is actually causing the issue. I used to think the only issue caused by a bad APU was the loading and then freezing at the publisher splash screen issue, but this experience taught me that I was wrong.

No, don’t worry, this isn’t my personal console. I got this one on eBay. Mine, of course, is immaculate, as you would expect. Incidentally, buy only from me or else this is the kind of thing that’ll show up at your doorstep after shopping online.

But wouldn’t you know it? This disgusting pile of filth and disease worked fine after I spent several hours washing it. I had to replace the capacitors, but otherwise it was fine. It’s aggravating that horrific-looking systems like this survive despite such neglect and abuse and yet so many well-cared for pristine-looking systems stored in safe and clean conditions by responsible, civilized people just die for no good reason.

I received a 3DS console today that had been cracked in half at the hinge. As I opened it up to remove the motherboard I immediately noticed that the tiny little IR board that normally connects to a plug next to the P7 connector was missing. The IR module on this motherboard was integrated and not removable. Also strange was the fact that the little piece of tape used at the factory to secure the touch screen connector was black, rather than the typical white. I’ve seen a few boards with black tape rather than white, but in the past I always assumed this was because they had already been worked on before I received them and the last technician had used black tape. Now I know I was probably wrong. This was an entirely new motherboard revision.

The back of the board

Integrated IR

There are some minor yet consistent differences I’ve noticed from one console to the next, such as the color of the mainboards, color of screws, slight variations in the labeling on the WiFi board, and the fact that most special edition consoles and consoles bundled with a game have the charge ports soldered much more securely to the board than the original black/red/blue models. Normally, however, the motherboard itself is basically the same. This is different from those types of minor variations because it’s a completely different motherboard revision from what I’ve seen before. Though it’s not something I normally pay attention to, I don’t think I recall ever seeing anything other than CTR-CPU-01 and the occasional CTR-CPU-20 boards.

The label on the WiFi daughterboard differs slightly from most models, but the board itself is the same DWM-W082 as all 3DS consoles.

In any case, this board does look more or less the same as any other model besides the fact that it has integrated IR and some silver screws in a few locations that normally have black screws. The color of the screws does differ from model to model, but I’ve never seen silver screws in these locations before. It’s fairly common for the external screws for the housing to be silver on special edition or bundled consoles, but I’ve never seen anything other than black for the screws beneath the SD card slot. Additionally, some special edition and bundled consoles have only two, rather than three, screws securing the L button in place and only three, rather than four, screws for the R button. This console follows that pattern but it also replaces the normal black screws for the shoulder buttons with silver ones.

Silver, rather than black, screws beneath the SD card slot.

Silver, rather than black, screws for the shoulder buttons as well

Unfortunately, the previous owner used super glue in a misguided attempt to repair the cracked housing and even glued the battery cover in place, leaving no possibility of salvaging it. But the serial number sticker inside was still legible:

For now I’m keeping this board. I put it inside one of my own consoles and sold the motherboard it replaced. I’ll probably keep it around for a while to tinker with and maybe I’ll eventually sell it.

One of the most common problems people seem to have with Super Nintendo consoles is they find that the console powers on but only displays a black screen with no audio, even with known good games. I don’t have a tremendous amount of experience repairing Super Nintendos, but it is something I do occasionally for fun and because I find that I usually learn something in the process. I generally stay clear of consoles with this type of problem though, since it could be caused by just about anything. Determining the exact cause can be next to impossible. Normally these boards look perfectly fine visually, so figuring out where there’s a broken trace can take forever. They’re usually not worth repairing. Sometimes, however, you get lucky and there’s something very obviously wrong that you can see visually. It still may take some careful inspection with a magnifying glass, but if there are any signs of corrosion or other damage, it’s always worth trying to fix it, even if it doesn’t look that bad visually or strike you as something that’s likely to be the cause of your problem.

You can see here I’ve put down a bit of solder along a trace running near U15. This trace had been broken due to corrosion, but it was so tiny that, rather than fix it with a wire, I just lay down a bit of solder along the broken length of it to repair the problem.

I wish I had taken a photo prior to the repair, but the opening photo up above shows the area where I found damage on this GPM-02 board. There are two audio RAM chips in the opening photo. U15, shown here to the left, is the one where there was a problem. Pin 12 of U15 had a bit of corrosion on it. I checked for continuity between it and the via it was going to and the connection was not totally broken, but it wasn’t exactly sound, either. If I fiddled with the multimeter probes I would get continuity, but it wasn’t consistent. Something told me to try using a wire to connect pin 12 directly to that via, just to see if it would help things. I put a bit of flux in the via, insert the tinned end of a small wire into it, crossed my fingers, and hoped that the solder would flow into the via and secure the tip of the wire in place. Fortunately it worked out as I had hoped and I was able to solder the other end of the wire to pin 12.

Without really thinking there would be any improvement, I went ahead and tested the console. To my surprise my test game worked fine. I then tested with about a dozen other games and they all worked. I was very surprised that this broken trace would cause a black screen for all games. Since mostly audio-related stuff goes on in this area of the board, I would have expected that symptoms of this type of damage might have been games playing but without any audio.

It’s not pretty, but it works.

In the end, I’m not sure if the damaged trace running near U15 actually had anything to do with the black screen problem. It was the first thing I noticed though when I opened the console, so I thought scraping away the corrosion and patching it was worth a shot. Fixing it alone didn’t solve the black screen problem though. Before reassembling I tested the console without the wire from pin 12 to the corresponding via and was able to reproduce the black screen problem, so a bad connection to/from pin 12 was clearly responsible for the issue. The other damaged trace may not have even been bad enough in the first place to cause a problem.

Though it looks pretty sloppy, when reassembling the console I simply placed a bit of electrical tape over the blobby length of solder on the patched trace. The console has been working fine for some weeks now, so it seems nothing is shorting.

This is the same console owned by the blighted mudcrab whose shoulder buttons I had the pleasure of cleaning previously.

While unresponsive shoulder buttons are far more common, sometimes the face buttons of a 3DS or other console become sticky or unresponsive. If the button works when pressed very hard but not when pressed lightly, it’s almost certainly due to dirt accumulation. If the button feels sticky or jammed, it’s most likely because there’s dirt built up around and beneath the plastic buttons, as in the above photo where thick rings of filth have built up around the circumference of each button. If the button doesn’t feel jammed but it’s not as clicky as it once was, it may be due to dirt under the conductive pads on the motherboard. In either case, it’s necessary to remove the motherboard from the housing (or at least remove the screws securing it in place and flip it over, if you’re in a hurry, like I was).

Here’s the rubber pad between the plastic buttons and the contacts on the motherboard. Doesn’t look too bad, does it?

But peel it away to reveal a cache of shit and grease.

Remove the buttons one by one and clean the slots. Toothpicks help.

Clean the buttons, too. As you can see, they’re usually even dirtier than the slots in which they sit.

Of course, while you’re at it you should also clean the D-pad and power buttons. It’s the same nauseating process as for the ABXY buttons, so I didn’t bother photographing them. When you have to disinfect your camera after each part of the process, you’ve got a strong incentive only to photograph the most essential steps.

Don’t close up your console yet. The most important part is to clean the contacts on the motherboard. If you’re a particularly depraved slimebucket—or if the console has suffered liquid damage—you should clean beneath the contacts as well.

As with most things, these contacts don’t look too bad from afar.

But look more closely and you’ll be horrified. We need to clean this sludge off with isopropyl alcohol and a cotton swab.

For the worst cases you will need to clean beneath the contacts as well. Mainly this is only necessary when there was liquid damage, but in this particular case the owner was such a slovenly clodhopper that there was a horrifying amount of dirt underneath the contacts even in the absence of anything else that looked like liquid damage.

You can peel the contacts up with a toothpick, but I actually find it easier to use my fingernail. As long as you’re careful, you can just stick them back down on the board when you’re finished cleaning. The adhesive is very strong, so it can be reused. However, if you do accidentally destroy the contacts you can replace them either from another motherboard or by buying replacements on eBay or Aliexpress for about $2, so there’s no great risk involved here. Just don’t scratch the motherboard.

It’s amazing the D-pad worked at all with this level of accumulation.

When cleaning it’s fine if you don’t remove 100% of the dirt. It’s not necessary to be perfect. In this case the contacts are clean enough to restore completely normal functionality even though there is still a small amount of stubborn dirt left that I couldn’t remove.

And that’s it. If people weren’t such swine none of this would be necessary.

Well, have maybe you’re a swamp dwelling slimelord, like the previous owner of this console.

The above is about average for consoles I receive. I’ve seen much worse, but it never ceases to surprise me how much dirt can accumulate inside consoles that look to be in decent cosmetic condition externally. This is the first time I had the idea to actually photograph it though. I doubt most people realize how much material gets transferred from their hands to the console and becomes trapped inside when they fail to wash their hands before playing.

I always clean beneath the shoulder buttons before selling a used console. I used to only do this for liquid-damaged consoles, but I’ve noticed it’s often necessary even on consoles that look like they’ve been taken care of responsibly. So now I don’t even bother testing the shoulder buttons first to see if they need it. I just assume they do and clean them.

Unresponsive shoulder buttons are almost always due to dirt accumulation. It’s really amazing what slobs people are. Fortunately, cleaning the shoulder buttons is very quick and easy, so even destitute mud farmers like the people who let this happen to their consoles can fix it themselves.

The left and right sides are pretty similar, so I only took photographs of the right side to show the process.

This is what we will be contending with on the right side.

The left is not much better.

First we remove these four black screws. On some consoles there will be only three.

Now we life the plate off and set it aside.

Next we life off this black plastic bracket.

The button is held in place by a peg and a spring. Carefully remove them.

This would be the moneyshot.

The best way to clean is with isopropyl alcohol. Not only does it make removing even tough dirt easy, it also eliminates most odors, which may be important if there’s liquid damage. You can do a good job with just a combination of a toothbrush, toothpicks, and some cotton swabs. Obviously you’ll want to focus your cleaning on the recess in which the plastic button sits, but you should also clean the button itself. If you’ve noticed that your shoulder buttons are unresponsive and don’t make as much of an audible “clicking” noise as they once did when you press them, cleaning them can sometimes help with that

Now we clean and dry the left side…

and the right side.

While you have the console open, it’s also a good idea to clean out the area beneath the SD card slot and the slot in which the stylus is stored.

Until you open it up to check, you would never suspect how much dirt can be trapped in these areas.

Remove the four silver screws that secure the stylus holder and SD card slot cover in place.

Disgusting.

Much better.

Reassembly is easy as long as you haven’t lost anything along the way.

Make sure these two nuts are in there. The four screws on the battery cover screw into these.

First, place the plastic part of the button into the recess.

Then insert the peg…

…and the spring.

Now we can insert the button itself.

Next we replace the black bracket on top of the button. The ribbon cable for the button goes through a slot in the bracket.

Replace the serial number plate and screw it back in. Take note that no screw goes in the upper left corner.

Here’s what the left side should like like in the end.

The finished, disinfected product.

If I get around to it I might write about how to repair most cases of sticky/unrepsonsive face buttons next. If I get around to it.

I repair a lot of 3DS consoles, mostly for fun. But unfortunately I also fail to repair a lot of 3DS consoles. For every 10 consoles I repair, there may be two or three that get tossed into the graveyard box. Eventually, I accumulate enough parts in the box to assemble a working console out of them.

Recently I was surprised to find that I had a good upper LCD, speakers with a good ribbon cable, and a few camera modules. I always have a surplus of lower screens and touch screens for some reason, so I had what was more or less a full console in individual parts. I decided that I would try once again to repair a heavily corroded motherboard that I had given up on recently. Fortunately it turned out all it needed was some elbow grease. Nothing was permanently damaged from the liquid it had been exposed to.

Unfortunately, I didn’t have a full housing set. I didn’t want to wait though until enough housing fragments found their way into my spare parts box, so I combined two different colors into what turned out to be what I think is a very sharp-looking console. Even though there’s only two colors, the parts actually came from at least four or five different consoles with varying degrees of wear and tear. Since it was assembled from parts that I had rejected in the first place as unsuitable for individual resale, I didn’t expect it would turn out quite as nice as it did.

This entire blog entry is about why I no longer avoid liquid-damage auctions as much as I used to, but even I wouldn’t mess with this shit.

One of the greatest things I’ve recently discovered about repairing 3DS consoles — and any small electronic gadget in general — is that I really don’t need to be avoiding “liquid damage” items as I once thought. Now, with mobile phones there’s the ick factor involved, since we’ve all seen people who use a mobile phone while in the restroom and, of course, when you see a liquid damaged mobile phone in an auction you can’t help but wonder if it fell in the toilet. That’s something I’m still not sure I would want to mess with. When it comes to 3DS consoles, however, the risk of the item touching shit or piss is far less since I think that the number of people who use a 3DS while on the toilet is far less than the number of people who use mobile phones while on the toilet. In other words, it’s not zero, but it’s a relatively low risk.

With mobile phones you more often have damage caused by the phone becoming completely submerged in a liquid (such as toilet water or a puddle in the street). However, because of the nature of a 3DS it’s more likely that liquid-damaged 3DS consoles experienced spillage, rather than submergence. It’s easy to imagine a clumsy person sitting, let’s say, on the couch with a beverage on the coffee table. Maybe this clumsy person sets the 3DS down next to the beverage and the beverage somehow spills. Spillage means that it’s often the case that the screens are not damaged and that there is less time in contact with the liquid , which means less widespread corrosion.

I have repaired six or seven heavily liquid-damaged 3DS consoles and, contrary to the warnings I see all the time, I haven’t yet seen one with any blown fuses. I’ve read warnings all over the place about liquid damaged consoles where people cry wolf, “It’s a waste of money because they all have blown fuses which are too hard to replace so you end up replacing the whole motherboard instead”. That’s hogwash.

When I get a liquid-damaged console I first take some WD-40 and spray a bit into each external screw hole. I let the console sit for about 45 minutes before attempting to open it. This is because the screws rust easily. I sometimes have to use WD-40 even for non-liquid-damaged consoles, but in the case of liquid-damage it is especially important because if you try to remove those small screws when rusty you can very easily strip them.

99% alcohol and a soft toothbrush are the main tools here. Yes, it’s pretty low-tech, but you often don’t need much of anything else. I take out all the internal screws, remove the WiFi board, SD card slot, analog stick, IR sensor, camera, and speaker ribbon cables. I take the motherboard out and scrub it clean with the alcohol and toothbrush. It’s fine to be rough on the board. Nothing will come off the board. It’s all soldered on there well. The key is to get every nook and cranny. The fuses are most likely fine. Let it dry and hold a battery to the connector. If it works, great. Connect screens and speaker and try to power on. If it works, reassemble. If no power, keep scrubbing. If still no power after cleaning the board very well, then get out a multimeter and do a continuity test on the fuses.

I recently had a console with only slight liquid damage near the battery connector area and it exhibited strange symptoms. I had scrubbed and scrubbed and scrubbed the board front and back to pristine condition, but the trouble persisted. The symptom was that the instant you pressed the battery to the connector the orange charge light would immediately turn on and one to two seconds later it would boot on its own. Once powered on it both charged and functioned totally normally and you could press the power button to turn it off. However, once you turned it off, the only way to power it back on was to remove the battery and then re-connect it, at which point the orange light would turn on again and it would power on one to two seconds later. I had no idea what was wrong, so I set it aside for a while and worked on some other consoles. A few days later I decided to turn it on to check all the other functions to make sure they still worked. When I tested WiFi I got the “An error has occurred. Press and hold the POWER Button to turn the system off. Please refer to the Operations Manual for details” message. This was strange, since WiFi had worked when I first tested it after cleaning the board. Nevertheless, I took a Post-it note, wrote “check wifi board” on it, and stuck it to the console and set it down for a few more days. Eventually I had some spare time one day and decided to open the console back up and check to see if the WiFi board was loose. I popped it off and just as I did so, I noticed the tiniest bit of corrosion just peeking out from beneath the metal frame on which the WiFi board rests. I took a spudger and lifted up the metal frame and, sure enough, there was some sludge under there.

Just this tiny amount of corrosion was enough to break WiFi and cause weird power and battery problems.

Thirty seconds of scrubbing cleaned the area up. I bent the metal frame back into place, popped the WiFi board back on and, sure enough, this fixed all the problems with the 3DS. Yes, it fixed the battery and power issues, too. The charge light no longer turned on when I connected a battery. It no longer booted automatically as soon as the battery was connected. WiFi worked. I could turn it on and off reliably using the power button. Just this small amount of contamination can mess your system up. The good news though is that, once you find it, it’s generally very easy to clean and fix the problem.

Changing gears here, another reason that people avoid liquid-damaged consoles is because, there’s a widespread belief that a liquid-damaged LCD must be replaced. It’s common to see mobile phones that the owner put in rice or something after getting them wet to save the motherboard. And sure, those phones work, but if you look at the LCD you see those drying marks that get left behind. Even quickly putting a device in a bag of rice doesn’t necessarily save it from those drying marks, often described by unscrupulous eBay sellers as “cloudiness” of the LCD. “Cloudy LCD” means “device dropped in the toilet” in eBay doubletalk. It’s like how “genuine” means “it is tangible” and not “it is made under license from the IP owner”. Anyway, those LCDs don’t necessarily need to be replaced. You can remove those drying marks. While you can’t restore the LCD to like-new condition, you can make it good enough for resale in many cases.

Now, I don’t know the proper terminology or even how exactly an LCD works, but it doesn’t really matter for my purposes. The LCD has several “papery” layers behind it. There is a reflective layer, then a backlight, then a slightly transparent white layer, and then some others that I forget the order of. We need to wipe all of those papery layers clean, since that’s where the drying marks are. When the backlight shines, those drying marks are made visible on the screen. In other words, it’s like taking the greasy wrapper that a burrito came in and holding a flashlight in front of it. If you do so, all the grease marks become more prominent on the semi-transparent burrito wrapper. But unlike a burrito wrapper, the papery layers behind the LCD can be cleaned with tap water. I use about 50% alcohol and 50% tap water. I originally used 99% alcohol but I found that it was too strong and left streaks. Tap water on its own will work fine though. I just use the 50% alcohol to help it dry faster.

Open the metal frame of the LCD and the backmost layer is this shiny one. On the left is the metal frame.

In this picture the LCD is on the left. On the right are the various layers and backlight that must be cleaned.

Anyway, just remove the metal frame in which the LCD is held. On the 3DS there are some clips that you can open using your fingernails. Above is what it looks like when you open up the top LCD of the 3DS. The first (backmost) layer is the shiny one. The easiest way I’ve found, so far, to clean these things without getting any marks or fingerprints on them is using a combination of one pair of microfiber eyeglass cleaning cloths and a pair of rubber-tipped tweezers. We must clean both sides of each layer, so it’s important to make a plan of action before we start. I put the microfiber cloth over my fingertip and hold the layer down as I clean it using a cotton swab and a half tap water half alcohol solution. I then dry it using a second microfiber cloth (while holding it down using my fingertip covered by the first microfiber cloth). I flip the layer over using the rubber-tipped tweezers and repeat on the back. After doing this for each layer I close the screen up and test.

Yes, that’s a coffee maker in the upper left. The kitchen is the only place with the right lighting for this type of cleaning. Checking for smudges or specks of dust is important and good lighting is indispensable. There’s nothing worse than screwing a console back together only to find that you have overlooked a speck of dust remaining under the LCD.

To test we need to connect the lower LCD, speakers, and upper LCD to the motherboard. The two little ribbons cables from the upper LCD must be connected to the appropriate connectors on the speaker/3D/brightness ribbon cable. It’s a tough balancing act connecting all those things, holding the battery in place, and taking a photograph all at the same time!

We check for streaks, dust, or any other blemishes at this point, since it would be a colossal pain in the ass to install the upper LCD, camera, speakers, WiFi antenna, and reassemble the housing only to find afterwards that there was some schmutz left under the LCD. Yes, this has happened to me before and no, you would not have wanted to be in the room at the time.

In the end this screen was 100% fixable. Sure, replacing it would be less work, but you can save money by cleaning it instead.

To connect this to my earlier point, it is far easier to clean these LCDs and get them in excellent condition suitable for resale when the liquid damage was of the spillage variety, rather than submergence. I’ve had some LCDs that I tried this process on that were just not salvageable because there was so much dirt in there that I couldn’t clean it all off without leaving streak marks. But if there are just some drying marks here and there on the LCD there is a good chance that you can clean them off well enough that you would never be able to tell there was liquid damage afterwards. Although 3DS screens are rather inexpensive, this can save you some money on parts, especially if both screens are liquid-damaged.